F-111 Aardvark / EF-111 Raven, General Dynamics

The swing-wing F-111 was designed as a multi-role aircraft, but ended
as an attack/strike aircraft. It was the result of an unwise and
unhappy attempt to fulfill different USAF and Navy requirements with
a single aircraft. The F-111B shipboard fighter, developed in
cooperation with Grumman, was a complete failure. The F-111 strike
fighter itself had a difficult start, but accumulated a good service
and combat record in later years. Production was 563 aircraft. One
F-111A was modified to the RF-111A/D configuration with cameras and SLAR.

The FB-111 is a strategic bomber development of the F-111. The FB-111 is longer and can
carry more fuel, but doesn't have real intercontinental range; this is
compensated by its missile armament.

The EF-111A is a modified F-111A. The F-111A was well-suited for modification to the
role of an airborne electronic warfare platform because of its structural strength,
maneuverability and performance -- including the ability to penetrate enemy airspace
and escape at supersonic speed. Exterior modifications include a narrow canoe-shaped
radome, about 16 feet (4.85 meters) long, mounted under the fuselage, which house antennas
for the high-powered jamming transmitters. Also, a fin-tip pod is mounted on the reinforced
vertical stabilizer to house receiving antennas and ancillary equipment, including a processor
to detect hostile radar emissions. The total equipment weight is about 3.5 tons (3,150 kilograms).

Interior modifications include a rearranged cockpit -- the right-seat crew member is an electronic
warfare officer responsible for navigation, terrain-following flight and electronic warfare
operations. The electronic warfare officer plans jamming tactics in advance, and then programs,
operates and monitors the jamming system. Previous radar-jamming aircraft required several operators
and more equipment to perform radar-jamming sessions. The primary electronic countermeasures unit is
the AN/ALQ-99E jamming subsystem. It is an improved version of the U.S. Navy's first ALQ-99 jamming
subsystem. Improvements to the Navy version include: capability to more rapidly detect and identify
enemy transmissions; greater automation (and less reliance on human involvement and manual operations);
expanded computer functions providing sophisticated and flexible jamming options; and more independent
jamming signals over a wider range of frequencies. The AN/ALQ-99E detects radar signals, processes
them and compares them to known threat radar characteristics stored in an on-board computer. Jamming
subsystem receivers scan across frequency bands under computer or manual control. When threats are identified,
appropriate countermeasures are initiated. Information about new threats, not in the memory of the computer,
can be fed into the system either through entries on the electronic warfare officer's cockpit keyboard or by
programming the computer via a cassette that plugs directly into the plane. Changing the programming takes
about five minutes if plug-in modules are used. The electronic warfare officer can test the information
and, if necessary, make corrections using the keyboard and cockpit display unit.

A self-protection subsystem is designed to protect the EF-111A against radar-directed, anti-aircraft artillery,
and missile or aircraft threats. The EF-111A provides protection by using a jamming orbit where it stands off
from threat radars to cover friendly aircraft entering and leaving the threat areas, or by using the aircraft's
high-performance capabilities to directly support attacking forces. In the direct support mission, the
Raven may fly as in escort position or enter a threat area to the best jammer position. Ravens engaged
in direct support often use the extensive night terrain-following capability built into the basic F-111 design.

The aircraft are being updated with modern digital navigation and flight-control systems, which equip the
airplane with ring-laser gyro and global-positioning navigation systems, as well as improved controls and
displays. The radar and terrain-following flight system are also being updated. Grumman modified about 40
F-111As to EF-111 configuration.

Mission

The F-111 is a multipurpose tactical fighter bomber capable of supersonic speeds. It can operate from tree-top level to altitudes above 60,000 feet (18,200 meters).

Features

The F-111 has variable-sweep wings that allow the pilot to fly from slow approach speeds to supersonic velocity at sea level and more than twice the speed of sound at higher altitudes. Wings angle from 16 degrees (full forward) to 72.5 degrees (full aft). Full-forward wings give the most surface area and maximum lift for short takeoff and landing. The F-111 needs no drag chute or reserve thrust to slow down after landing.

The two crew members sit side-by-side in an air-conditioned, pressurized cockpit module that serves as an emergency escape vehicle and as a survival shelter on land or water. In emergencies, both crew members remain in the cockpit and an explosive cutting cord separates the cockpit module from the aircraft. The module descends by parachute. The ejected module includes a small portion of the wing fairing to stabilize it during aircraft separation. Airbags cushion impact and help keep the module afloat in water. The module can be released at any speed or altitude, even under water. For underwater escape, the airbags raise the module to the surface after it has been severed from the plane.

The aircraft's wings and much of the fuselage behind the crew module contain fuel tanks. Using internal fuel only, the plane has a range of more than 2,500 nautical miles (4,000 kilometers). External fuel tanks can be carried on the pylons under the wings and jettisoned if necessary.

The F-111 can carry conventional as well as nuclear weapons. It can carry up to two bombs or additional fuel in the internal weapons bay. External ordnance includes combinations of bombs, missiles and fuel tanks. The loads nearest the fuselage on each side pivot as the wings sweep back, keeping ordnance parallel to the fuselage. Outer pylons do not move but can be jettisoned for high-speed flight.

The avionics systems include communications, navigation, terrain following, target acquisition and attack, and suppression of enemy air defense systems. A radar bombing system is used for precise delivery of weapons on targets during night or bad weather.

The F-111's automatic terrain-following radar system flies the craft at a constant altitude following the Earth's contours. It allows the aircraft to fly in valleys and over mountains, day or night, regardless of weather conditions. Should any of the system's circuits fail, the aircraft automatically initiates a climb.

Background

The F-111A first flew in December 1964. The first operational aircraft was delivered in October 1967 to Nellis Air Force Base, Nev. A models were used for tactical bombing in Southeast Asia.

Developed for the U.S. Navy, the F-111B was canceled before its production . F-111C's are flown by the Royal Australian Air Force.

The F-111D has improved avionics with better navigation, air-to-air weapon delivery systems, and newer turbofan engines. The F-111D's are flown by the 27th Fighter Wing, Cannon Air Force Base, N.M.

The E model has modified air intakes to improve the engine's performance at speeds above Mach 2.2. Most F-111Es serve with the 20th Fighter Wing, Royal Air Force Station Upper Heyford, England, to support NATO. F-111E's were deployed to Incirlik Air Base, Turkey, and were used in Operation Desert Storm.

The F-111F has Improved turbofan engines give F-111F models 35 percent more thrust than previous F-111A and E engines. The avionics systems of the F model combine features of the F-111D and E. The last F model was delivered to the Air Force in November 1976. The F models have been modified to carry the Pave Tack system in their weapons bays. This system provides an improved capability to acquire, track and designate ground targets at night for delivery of laser, infrared and electro-optically guided weapons.

The F-111F was proven in combat over Libya in 1986 and again over Iraq in 1991. Although F-111F's flew primarily at night during Operation Desert Storm, aircrews flew a particularly notable daytime mission using the Guided Bomb Unit (GBU-15) to seal the oil pipeline manifold sabotaged by Iraq, allowing the oil to flow into the Persian Gulf.

The F-111G is assigned to the 27th Fighter Wing at Cannon Air Force Base and is used in a training role only. The G model is a converted FB-111A. The conversion made minor avionics updates and strengthened the aircraft to allow its use in a more dynamic role as a fighter aircraft